The present invention generally relates to batteries and their uses. The invention particularly relates to an integrated current interrupt device for interrupting current within a battery in the event of a mechanical impact load.
Currently, the automotive industry is facing increased pressure from consumer demand for more fuel-efficient vehicles. To meet these requirements, as well as new regulations enforced by the Environmental Protection Agency, automotive manufactures have increasingly relied on battery power for automobile power. Unfortunately, the cost of manufacturing batteries is still relatively high, each additional battery increases the risk of an overcharge, and there are risks of explosions during accidents that have not yet been completely preventable. As such, industry is continuously attempting to both reduce the cost of manufacturing car batteries and improve their safety.
To improve upon safety, modern batteries generally comprise safety devices integrated in the cell design for overcharge and short-circuit protection. One type of safety device is an integrated current interrupt device (CID), which electrically disconnects the cell if internal pressures get too high. For battery cells with hard shell batteries (i.e., cylindrical and prismatic cells), the individual battery cells may have CID functionality for internal short circuits. Softer shell batteries (i.e., pouch cells) generally do not have CID functionality since the currently-accepted assumption in the battery industry is for the pouch/bag to simply open under high internal pressure inside the pouch. However, in the automotive industry, for instance, large numbers of battery cells are commonly constrained in the thickness direction thereof, and therefore the pouch cells may not be capable of opening freely as assumed. It is believed that no CID functionality is currently provided to any type of battery for mechanical impact loads.
Accordingly, there is an ongoing desire for methods or devices by which CID functionality may be provided to battery cells that interrupt current in the event of mechanical impact loads, for example, during an automobile accident.